1. Field of the Invention
This invention relates to anchor pin assemblies, and in particular to anchor pin assemblies for drum brakes. More particularly, this invention relates to an anchor pin assembly for drum brakes which will permit easy replacement of a deformed, worn and/or dislodged anchor pin.
2. Description of the Prior Art
Drum brakes having a pair of generally arcuate brake shoes pivotably mounted at one end to an anchor structure and selectively actuatable at the other ends thereof to pivot radially outwardly relative to the anchor structure to frictionally engage a brake drum are well known in the prior art. Usually, the brake shoes comprise an arcuate table carrying the friction material and at least one radially inwardly extending rib or web. Typically, the pivotably mounted ends of the brake shoe webs are formed with either generally concave surfaces or generally annular apertures which are pivotably supported by an anchor structure comprising a single anchor pin, or a pair of anchor pins, fixed to the brake spider. A resilient retaining member, or members, such as a coil tension spring may be utilized to retain the brake shoes against the anchor member. Examples of such prior art drum brakes may be seen by reference to U.S. Pat. Nos. 2,710,076; 3,398,814 and 3,467,229, all assigned to the assignee of this invention and all hereby incorporated by reference.
While these prior art devices are generally satisfactory and enjoy great commercial success, a problem has occasionally existed with the anchor pin, or pins, thereof. The anchor pins of the prior art devices were usually fixedly mounted to support structure, usually referred to as the brake spider, as by a staked press fit. When the anchor pins occasionally became loose, dislodged and/or otherwise damaged, it was difficult to replace same, especially if a press and/or specialized fixtures were not readily available, and often a new spider assembly was required. In certain types of brakes, such as trailer axle brakes, wherein the spider was welded, or otherwise nonremovably attached, to an axle housing, this situation was particularly unsatisfactory.